ENTSOG TYNDP 2017 - Annex F - Methodology

4.2 MODELLING-BASED INDICATORS

In the following description, the term “Zone” will generally be used to refer to a coun- try. In some instances it refers to a balancing zone. The relevant Zones can be found in the annex E where the respective indicator is shown.

4.2.1 Remaining Flexibility (RF)

This indicator measures the resilience of a Zone as the additional share of demand each country is able to cover before no longer being able to fulfil its demand without creating new demand curtailment in other Zones. The value of the indicator is set as the possible increase in demand of the Zone before an infrastructure or supply lim- itation is reached somewhere in the European gas system. This indicator will be calculated under 1-day Design Case and 14-day Uniform Risk situations with and without supply stress. The Remaining Flexibility of the Zone Z is calculated as follows (steps 2 and 3 are repeated independently for each Zone): 1. Modelling of the European gas system under a given climatic case 2. Increase of the demand of the Zone Z by 100% 3. Modelling of the European gas system in this new case The Remaining Flexibility of the considered Zone is defined as 100% minus the percentage of disruption of the additional demand. The higher the value, the better the resilience is. A zero value would indicate that the Zone is not able to fulfil its demand and a 100% value will indicate it is possible to supply a demand multiplied by a factor two.

4.2.2 Disrupted Demand (DD) and Disrupted Rate (DR) The amount of disrupted demand for a given Zone is provided: \\ In energy (DD) \\ As relative share/percentage (DR)

This amount is calculated in a Cooperative mode, that is, under the flow pattern maximising the spreading of the disrupted demand (in order to reduce the relative impact on each Zone). This means that, if possible, all the Zones will share the same disrupted rate

4.2.3 Uncooperative Supply Source Dependence (USSD)

This indicator identifies Zones whose physical supply and demand balance depends strongly on a single supply source when each Zone tries to minimise its own depend- ence (the Zones closest to the considered source are likely to be the more depend- ent). It is calculated for each Zone vis-à-vis each source under a whole year as the suc- cession of an Average Summer and an Average Winter. The Supply Source Dependence of all Zones to source S is calculated as follows (steps 1 to 4 are repeated for each source): 1. The availability of source S is set down to zero 2. The availability of the other sources is not changed 3. The cost of disruption is set flat and at the same level for each Zone 4. Modelling of the European gas system under the whole year

Ten-Year Network Development Plan 2017 Annex F: Methodology | 17